Question: When did Oskar Lafontaine become the head of the government of Saarland?
Paraphrase: At what point in time did Oskar Lafontaine become the head of the government of Saarland?
SPARQL (Wikidata): SELECT ?value WHERE { wd:Q1201 p:P6 ?s . ?s ps:P6 wd:Q110719 . ?s pq:P580 ?value}